Tropospheric ozone assessment report phase-II: ozone interactions with climate change: drivers and long-term trends

Szopa, S., Cooper, O. R., Collins, B. ORCID: https://orcid.org/0000-0002-7419-0850, Fiore, A. M., Lee, J., Lin, M., Lu, X., Naik, V., Turnock, S. T., West, J. J., Chang, K.-L. and Wang, H. (2025) Tropospheric ozone assessment report phase-II: ozone interactions with climate change: drivers and long-term trends. Philosophical Transactions A. doi: 10.1098/rsta.2025-0272 (In Press)

Abstract/Summary

This Tropospheric Ozone Assessment Report Phase-II study has assessed the current state of knowledge regarding ozone’s important role as a short-lived climate forcer, as well as the influence of climate change on global tropospheric ozone, relying on new studies published within the past five years. Models estimate that the tropospheric ozone burden has increased substantially since the pre-industrial, supported by available measurements, contributing to a radiative climate forcing from total column ozone of 0.50 [0.25 to 0.75] W m-2 for 1750-2024, making ozone the third most important anthropogenic greenhouse gas. Since 1990, surface, airborne and satellite measurements, as well as models, suggest a continued rise in the tropospheric burden, although ground-level ozone is decreasing in some regions. This is driven in part by the continued rise of methane, despite estimates that global anthropogenic NOx emissions may have peaked recently. Climate change influences ozone through a variety of physical, biological and chemical processes. Increasing temperatures are expected to reduce global average surface ozone, due to increased water vapor, but increase ozone in polluted regions. Future surface and free tropospheric ozone concentrations will be determined by a 40 complex interplay of emissions changes, as well as by climate change and land-biosphere feedbacks.

Item Type	Article
URI	https://centaur.reading.ac.uk/id/eprint/131565
Identification Number/DOI	10.1098/rsta.2025-0272
Refereed	Yes
Divisions	Science > School of Mathematical, Physical and Computational Sciences > Department of Meteorology
Publisher	Royal Society
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